Wolcott, who had moved to Chicago in 1810, probably introduced Juliette to John H. Kinzie, son of fur trader John Kinzie.[2] They married in 1830 and moved to Detroit and then Fort Winnebago, a new trading post at the crucial portage between the Fox and Wisconsin rivers. Her husband was an Indian sub-agent to the Ho-Chunk nation (Winnebago people), assigned to this area that connected the Great Lakes/St. Lawrence and Mississippi watersheds.[3]

Members of the Kinzie family, particularly her mother-in-law and sister-in-law, told Juliette about the Battle of Fort Dearborn at Chicago. Being Canadians, they were not attacked (it was during the War of 1812), and evacuated to Detroit. In 1844 Kinzie published Narrative of the Massacre at Chicago, August 15, 1812, and of Some Preceding Events, anonymously, but acknowledged authorship soon after publication.

Her second book Wau-Bun: The "Early Day" in the North West,[6] extended her first book. It recounted her experiences at Fort Winnebago in the early 1830s, as well as those of her mother-in-law and other relatives during the Black Hawk War. The title reflects the local word for daybreak. Kinzie described her journeys back and forth to the early settlement of Chicago, and complex cultural encounters with a diverse frontier society. Unusual for its day, the book also described sympathetically and in detail the lives of Native Americans, who were being displaced by her extended family and other white settlers. An appendix included excerpts from the journals of relative Thomas Forsyth, who blamed the United States (rather than the Sauk) for starting the war.[7] Published by Derby and Jackson in 1856, it was reprinted 19 times by the end of that century, and four more times in the 20th century.[8][9] At least one 20th century historian found it unduly romantic, and criticized it for exaggerating the importance of her relatives, particularly her father-in-law.[10]

In 1869 her novel Walter Ogilby was published. Her Narrative... was reworked and released as Mark Logan, the Bourgeois in 1871 following her death.

Juliette and John Kinzie had seven children, six of whom survived to adulthood. John Kinzie served as U.S. Army paymaster for Michigan, Wisconsin and Illinois troops in the Civil War and died of a heart attack on his way to a vacation shortly after President Lincoln's assassination. One son died fighting for the Union in the Civil War, two others were taken prisoner by Confederate forces but survived.